DESCRIPTION (As Adapted from the Investigator's Abstract): Current research demonstrate that common physiologic response to pain in infants include increased heart rate, blood pressure, and intracranial pressure, as well as decreased oxygen saturation. These parameters directly impact cerebral blood flow, thereby increasing the risk for intraventricular hemorrhage (IVH) a major cause of morbidity and mortality in the neonatal intensive care unit. The purpose of this research is to describe the phenomena of cerebral blood flow velocity as a response to an acute nocioceptive event, the heel stick, which includes all phases of a heel stick procedure. The specific aim is to compare the response in cerebral blood flow velocity of the heel stick with the non-nocioceptive event, heel prep. The proposed pilot study will have a randomized two-period, two-treatment, crossover design. Infants will serve as their own control; each infant will receive both treatments. Twenty subjects will be selected via a sample of convenience and then randomized to one of two groups. Groups will differ for order of treatment. Observations will be made at baseline and than at six time points following each treatment for a total of 13 observations for each infant.